Multi-touch system and driving method thereof

ABSTRACT

Provided are a multi-touch system and a driving method thereof. The method includes, extracting using a digital processor a touch frequency and at least one angle associated with at least one touch from image information captured by each of at least two cameras, selecting a touch mode on the basis of sum value of the touch frequencies extracted from the image information captured by the cameras, and performing a touch function corresponding to the selected touch mode using a user interface.

This application claims the benefit of Korean Patent Application No.10-2008-0032501, filed on Apr. 8, 2008, which is hereby incorporated byreference in its entirety for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a multi-touch system, and moreparticularly, to a multi-touch system that can realize a variety offunctions using multi-touch, and a driving method thereof.

2. Discussion of the Related Art

With the development of an information-oriented society, display devicesfor delivering information to a user are being actively developed

Information may be provided to the display device by various inputdevices, for example, a mouse and a keyboard, and can be output fordelivery to a third party using various output units, for example, aprinter and a fax unit.

However, as various input/output devices are connected to the displaydevice, the areas occupied by the input/output devices increase, and thenumber of connection lines between the display device and theinput/output devices increases.

Therefore, a display device having an input/output function therein isunder development recently.

For example, a mouse function is added to a display device, so that aseparate mouse device does not need to be connected to the displaydevice.

To realize an input function in a display device, a device that canrecognize the touch operation of a user is required.

The recognition device can be realized in a capacitance type, aresistance type, an infrared (IR) matrix type, or a camera type.

In the capacitance type and resistance type recognition devices, avariable material that varies capacitance or resistance is included inthe panel of a display device, so that the touch operation of a user canbe recognized as capacitance or resistance changes due to the touchoperation of the user.

In the IR matrix type recognition device, infrared sensors generatinglight are disposed at a corner on one side of the panel of the displaydevice, and photo sensors receiving light of the infrared sensors aredisposed on a corner on the other side, so that the touch operation ofthe user can be recognized.

In the camera type recognition device, two cameras are installed in theedge regions of the display device to generate the touch operation of auser in the form of an image, so that the touch operation of the usercan be recognized.

However, the camera type recognition device can perform only onefunction corresponding to one touch. (For example, there are some iconsdisplayed on a panel and each only correspond to one function. When theuser touches one icon on the panel and the touch is recognized and thefunction corresponding to the touch is performed by it too). Therefore,various functions cannot be performed.

Recently, a type of recognition device that can perform variousfunctions corresponding to multi-touch is studied but a specificrealization method has not been proposed up to now.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a multi-touch systemand driving method thereof that substantially obviates one or more ofthe problems due to limitations and disadvantages of the related art.

Embodiments provide a multi-touch system that can realize a multi-touchto perform various functions, and a driving method thereof.

Embodiments also provide a multi-touch system that can perform variousfunctions corresponding to multi-touches in a camera type or an IRmatrix type, and a driving method thereof.

Embodiments also provide a multi-touch system that can perform variousfunctions by connecting a multi-touch with an operating system (OS), anda driving method thereof.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. These andother advantages of the invention will be realized and attained by thestructure particularly pointed out in the written description and claimshereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, a methodfor driving a multi-touch system includes: extracting using a digitalprocessor a touch frequency and at least one angle associated with atleast one touch from image information captured by each of at least twocameras; selecting a touch mode on the basis of sum value of the touchfrequencies extracted from the image information captured by thecameras; and

performing a touch function corresponding to the selected touch modeusing a user interface.

In another aspect of the present invention, a multi-touch systemincludes: a touch recognition unit generating at least two imageinformation; a digital processor calculating a frequency of touch andangles from each image information; a controller selecting a touch modein response to the sum value of the calculated frequency of the touchfrom the at least two image information; and a user interface performinga touch function corresponding to the touch mode.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention.

In the drawings:

FIG. 1 is a block diagram of a multi-touch system.

FIG. 2 is a block diagram illustrating the touch recognition unit ofFIG. 1.

FIG. 3 is a view illustrating the touch recognition unit of FIG. 1disposed on a panel.

FIGS. 4A and 4B are views illustrating image information generated byeach camera.

FIG. 5 is a view illustrating an overlap of a touch.

FIGS. 6A and 6B are views illustrating image information generated byeach camera for the overlapped touch of of FIG. 5.

FIG. 7 is a view illustrating a table including the frequency of touchand a touch mode.

FIG. 8 is a view illustrating a method for calculating a new touchpoint.

FIG. 9 is a flowchart explaining a method for driving a multi-touchsystem according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Reference will now be made in detail to the embodiments of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings.

In this description, a multi-touch refers to a touch by a plurality offingers at a time. For example, a two-touch means two of ten fingers ofa user are touched at a time, and an eight-touch means eight of tenfingers of the user are touched at a time.

Embodiments of the invention may employ at least two cameras. When amulti-touch is recognized using two or more cameras, actual touch pointsas well as virtual image touch points can be calculated. The actualtouch points are points actually touched by a user, while the virtualimage touch points are virtual points obtained by calculation. Thevirtual image touch points are indispensably computed in the case wherethe multi-touch is recognized by two or more cameras.

For example, in case of a two-touch as illustrated in FIG. 3, two actualtouch points A and B and two virtual image touch points C and D can becomputed.

According to an embodiment of the invention, the frequency of touch ofactual touch points touched at a time is computed, and differentfunctions can be performed according to the computed frequency of touch.Therefore, according to an embodiment, different functions can beperformed according to the frequency of touch of actual touch pointsactually touched and displayed by each camera.

FIG. 1 is a block diagram of a multi-touch system, FIG. 2 is a blockdiagram illustrating the touch recognition unit of FIG. 1, and FIG. 3 isa view illustrating the touch recognition unit of FIG. 1 disposed on apanel.

Referring to FIG. 1, the multi-touch system 10 can include a touchrecognition unit 20, a digital processor 30, a controller 40, anoperating system 50, a user interface 60, a panel 70, and first andsecond memories 80 and 85.

The panel 70 can be any display panel capable of displaying an image.For example, the panel can be one of a liquid crystal display panel, aplasma display panel (PDP), an organic electro-luminescence displaypanel, a light emitting diode panel, and a field emission display (FED)panel.

Referring to FIG. 2, the touch recognition unit 20 includes the firstand second cameras 22 and 24.

Referring to FIG. 3, the first and second cameras 22 and 24 can bedisposed on the panel 70.

The panel 70 includes a display region 72 on which an image is displayedand a non-display region 74 on which an image is not displayed.

The first and second cameras 22 and 24 can be disposed on thenon-display region 74 of the panel 70. That is, the first camera 22 canbe disposed on the first corner region 76 of the non-display region 74of the panel 70, and the second camera 24 can be disposed on the secondcorner region 78 of the non-display region 74 of the panel 70.

The first and second cameras 22 and 24 are optical sensors and can, forexample, be complementary metal oxide semiconductor (CMOS) devices orcharged coupled devices (CCDs).

The display region 72 of the panel 70 has a quadrangular shape, with theangle at respective corner regions 76 and 78 of the display region 72being 90°.

Therefore, since the first and second cameras 22 and 24 disposed in thenon-display region 74 of the panel 70 should cover the display region72, the viewing angles of the first and second cameras 22 and 24 may bein the range of 0-90°. The fingers of the user touched on the displayregion 72 of the panel 70 can be recognized by the first and secondcameras 22 and 24 having this range of viewing angle.

Although only two cameras 22 and 24 are shown in FIG. 2, for thepurposes of illustration and description, the present invention is notlimited thereto, and the invention can be readily implemented usingthree or more cameras.

Referring to FIG. 3, in the case where a two-touch by a user's twofingers is made, the two-touch is recognized by the first and secondcameras 22 and 24 and generated as first and second image information asillustrated in FIGS. 4A and 4B. Touch points and the angles of the touchpoints can be displayed on each of the first and second imageinformation. The touch points mean points actually touched by the user.

The first and second image information of a touch generated by the firstand second cameras 22 and 24 is provided to the digital processor 30.

The digital processor 30 can extract the frequency of touches of touchpoints and the angle of each touch point from the first and second imageinformation provided by the first and second cameras 22 and 24.

For example, referring to FIG. 3, in the case where a two-touch is madeon the display region 72 of the panel 70, two times of the frequency oftouches and angles (a, b) can be extracted from the first imageinformation generated by the first camera 22, and two times of thefrequency of touches and angles (c, d) can be extracted from the secondimage information generated by the second camera 24.

The digital processor 30 can compute coordinates of two actual touchpoints A and B (referred to as first and second touch points) usingtriangulation technique on the basis of first and second angles a and bof each touch point recognized by the first camera and third and fourthangles c and d of each touch point recognized by the second camera.

When the coordinates of such actual touch points A and B are computed,virtual image touch points C and D corresponding to points not actuallytouched by a user can be generated. That is, in the case where the firstcamera 22 is connected to the touch point A by the first angle using afirst line, and the second camera 24 is connected to the touch point Bby a fourth angle d using a second line, a virtual image touch point Dcan exist at a point where the first and second lines cross each other.Additionally, in the case where the first camera 22 is connected to thetouch point B by the second angle b using a third line, and the secondcamera 24 is connected to the touch point A by a third angle c using afourth line, a virtual image touch point C can exist at a point wherethe third and fourth lines cross each other.

However, an embodiment can be realized even when the coordinates of thevirtual image touch points C and D cannot be traced because theembodiment uses the frequency of touches of actual touch points touchedat a time, rather than simply using the coordinates of the touch points.

In an embodiment, the coordinates of two actual touch points A and B canbe computed. That is, the first touch point A can be computed using thefirst angle a recognized by the first camera 22 and the third angle crecognized by the second camera 24. The second touch point B can becomputed using the second angle b recognized by the first camera 22 andthe fourth angle d recognized by the second camera 24.

Referring to FIGS. 4A and 4B, the angles of the first and second touchpoints A and B recognized by the first camera 22 can be the first andsecond angles a and b, and the angle of the first and second touchpoints A and B recognized by the second camera 24 can be the third andfourth angles c and d.

The digital processor 30 stores the frequency (i.e. the count) oftouches of actual touch points A and B extracted by the first camera 22,the frequency of touches of the actual touch points A and B extracted bythe second camera 24, and the coordinates of the actual touch points Aand B computed from angles a, b, c, and d extracted by the first andsecond cameras 22 and 24 in the first memory 80. Referring to FIGS. 4Aand 4B, the frequency of touches extracted by the first and secondcameras 22 and 24 can be two times.

Here, it should be noted that the frequency of touches actually made ata time by the user can be different from the frequency of touches oftouch points extracted by the respective cameras 22 and 24. For example,even when the frequency actually made at a time by the user is twotimes, the frequency of touches extracted by one of the first and secondcameras 22 and 24 can be one time.

Referring to FIG. 5, in the case where two times of touches are made inparallel to the recognition direction of the first camera 22, thefrequency of touches extracted by the first camera 22 can be one time asillustrated in FIG. 6A and the frequency of touches extracted by thesecond camera 24 can be two times as illustrated in FIG. 6B. That is, inthe case where two times of touches are made in parallel to therecognition direction of the first camera 22, first and second touchpoints a′ and b′ are parallel to the recognition direction of the firstcamera 22 and the first touch point a′ overlaps the second touch pointb′ and thus the second touch point b′ is not recognized by the firstcamera 22. Accordingly, the frequency of touches recognized by the firstcamera 22 can be one time. On the other hand, the frequency of touchesextracted by the second camera 24 can be two times, and is equal to thefrequency of touches actually made by the user.

A multi-touch panel according to an embodiment of the invention cancombine the frequency of touches extracted by the first and secondcameras 22 and 24 in consideration of the above circumstance to performdifferent functions corresponding to the frequency of touches without anerror in selecting the intended function, as will be described below.

A plurality of touch modes according to the frequency of touchesextracted by the first and second cameras 22 and 24 can be set as atable in the second memory 85.

Referring to FIG. 7, the correspondence between the summed frequency oftouches by the first and second cameras 22 and 24, and the correspondingtouch modes are set in the table set in the second memory 85. The summedfrequency of touches can be sum of the frequency of touches extracted bythe first camera 22 and the frequency of touches extracted by the secondcamera 24.

For example, when the summed frequency of the first and second cameras22 and 24 is two times, a touch mode can be set to ‘1’. When the summedfrequency of the first and second cameras 22 and 24 is one of threetimes and four times, a touch mode can be set to ‘2’. When the summedfrequency of the first and second cameras 22 and 24 is one of five timesto ten times, a touch mode can be set to ‘3’. When the summed frequencyof the first and second cameras 22 and 24 is one of eleven times totwenty times, a touch mode can be set to ‘4’.

In the example illustrated in FIG. 7, the touch mode ‘1’ is a mode forperforming a mouse left button, the touch mode ‘2’ is a mode forperforming a mouse right button, the touch mode ‘3’ is a mode forperforming a mouse scroll button, and the touch mode ‘4’ is a mode fortoggling the virtual keyboard on and off. When the touch mode ‘4’ isselected initially, a virtual keyboard is displayed on the panel 70.When the touch mode ‘4’ is selected again, the virtual keyboarddisplayed on the panel 70 may disappear.

When a user touches with his one finger, the summed frequency of touchesby the first and second cameras 22 and 24 can be two times. When theuser touches with his two fingers at a time, the summed frequency oftouches by the first and second cameras 22 and 24 can be three times orfour times. For example, in the case where a two-touch is overlapped andonly one touch is recognized by the first camera 22, and two times ofnumber of time of touches corresponding to the two-touch are recognizedby the second camera 24, the summed frequency of touches by the firstand second cameras 22 and 24 can be three times. However, if a two-touchis not overlapped by either of the first and second cameras 22 and 24,two times of the frequency of touches is recognized by the first camera22, and two times of the frequency of touches is recognized by thesecond camera 24, so that the summed frequency of touches by the firstand second cameras 22 and 24 can be four times.

The above sum computation of the frequency of touches by the first andsecond cameras 22 and 24 shows that at least five times of summedfrequency of touches can be made at a time by a user for the case of thetouch mode ‘3’, and eleven times of summed frequency of touches can bemade at a time by a user for the case of the touch mode ‘4’.

Referring again to FIG. 2, the digital processor 30 reads the angle ofeach touch point, the frequency of touches, and the coordinate of eachtouch point recognized by each of the cameras 22 and 24 and stored inthe first memory 80 and provides them to the controller 40.

The controller 40 computes a summed value of the frequency of touchesrecognized by the first and second cameras 22 and 24 and provided by thedigital processor 30, selects a touch mode corresponding to the computedsummed value from the table of the second memory 85, and provides acontrol signal corresponding to the selected touch mode to the operatingsystem 50.

For example, the controller 40 can select the touch mode ‘1’ from thesecond memory 85 and provide a first control signal corresponding to thetouch mode ‘1’ to the operating system 50 when the computed summed valueis 2.

The controller 40 can select the touch mode ‘2’ from the second memory85 and provide a second control signal corresponding to the touch mode‘2’ to the operating system 50 when the computed summed value is 3 or 4.

The controller 40 can select the touch mode ‘3’ from the second memory85 and provide a third control signal corresponding to the touch mode‘3’ to the operating system 50 when the computed summed value is one of5 to 10.

The controller 40 can select the touch mode ‘4’ from the second memory85 and provide a fourth control signal corresponding to the touch mode‘4’ to the operating system 50 when the computed summed value is one of11 or 20.

Meanwhile, each of the cameras 22 and 24 can recognize a user's touchcontinuously to generate corresponding image information. For example,when the respective cameras 22 and 24 are driven at 60 Hz, they cangenerate image information of 60 frames per second. When the respectivecameras 22 and 24 are driven at 120 Hz, they can generate imageinformation of 120 frames per second.

The above described first and second image information can be generatedat a specific time by the respective cameras 22 and 24.

In the case where a user touches the panel with at least two fingers,there is possibility that a small time difference is generated betweentouches by the fingers. When any finger is not touched due to a timedifference between the touches by the fingers of the user, a touch pointby the untouched finger is not formed on the first and second imageinformation generated at a specific time by the respective cameras 22and 24.

In this case, when the frequency of touches extracted by the respectivecameras 22 and 24 at a particular time are summed to select a touchmode, a false touch mode may be selected and consequently a false touchfunction may be performed.

To solve this false touch mode problem, in an embodiment of theinvention, the frequency of touches extracted from the first imageinformation generated by the first camera 22 for each frame in a set offrames and the frequency of touches extracted from the second imageinformation generated by the second camera 24 are summed, and the summedvalue of the frequency of touches is included in the summed frequency oftouches in real-time by the first and second cameras 22 and 24 forselection of a specific touch mode as illustrated in FIG. 7, thespecific touch mode can be finally selected. For example, the set framesof frames can be ten frames. To allow a specific touch mode, forexample, the touch mode ‘4’ to be selected, the summed frequency oftouches by the cameras 22 and 24 extracted from each frame in the rangeof 50-100% of ten frames should be included in the range of summedfrequency of touches by the first and second cameras 22 and 24 set tocorrespond to the specific mode.

For example, during a first frame, the frequency of touches extractedfrom the first image information by the first camera 22 and thefrequency of touches extracted from the second image information by thesecond camera 24 are summed and the summed value can be included in therange (11 to 20) of the summed frequency of touches by the first andsecond cameras 22 and 24 set to correspond to the touch mode ‘4’.

During second to seventh frames, the summed frequency of touchesextracted from the cameras 22 and 24 may be included in the range (11 to20) of the summed frequency of touches by the first and second cameras22 and 24 set to correspond to the touch mode ‘4’.

During eighth to tenth frames, the summed frequency of touches extractedfrom the cameras 22 and 24 may be included in the range (5 to 10) of thesummed frequency of touches by the first and second cameras 22 and 24set to correspond to the touch mode ‘3’.

In this case, since during seven frames of the total ten frames, thesummed frequency of touches extracted from the cameras 22 and 24 isincluded in the range (11 to 20) of the summed frequency of touches bythe first and second cameras 22 and 24 set to correspond to the touchmode ‘4’, the touch mode ‘4’ can be selected finally.

Though the number of frames is limited to ten in the embodiment, thenumber of frames is not limited thereto but the present invention can becan using a set of five frames, fifteen frames, twenty frames or moreframes.

Additionally, the controller 40 averages the angles of respective touchpoints to compute an average angle, and computes a new touch point and acoordinate thereof using each average angle. Here, the coordinate of thenew touch point can be used as a reference coordinate when a functioncorresponding to each touch mode is performed. For example, in the casewhere a mouse scroll button corresponding to the touch mode ‘3’ isperformed, an image disposed on the panel 70 can be moved to any one ofup, down, left, and right directions. The reference coordinate can beused as a reference position for movement of an image.

A new touch point and a coordinate thereof computed by the controller 40can be stored in the second memory 85.

For example, referring to FIG. 8, for a first touch point A and a secondtouch point B touched by a user, the angle of the first touch point Aextracted by the first camera 22 is a, the angle of the second touchpoint B extracted by the first camera 22 is b, the angle of the firsttouch point A extracted by the second camera 24 is c, and the angle ofthe second touch point B extracted by the second camera 24 is d.

The coordinate (X1, Y1) of the first touch point A can be computed usingthe angles a and c extracted by the first and second cameras 22 and 24,and a distance between the first and second cameras 22 and 24. Thecoordinate (X2, Y2) of the second touch point B can be computed usingthe angles b and d extracted by the first and second cameras 22 and 24,and a distance between the first and second cameras 22 and 24.

Additionally, an angle q1, (where q1=(a+b)/2) can be computed by theaveraging of the angles a and b extracted by the first camera 22, and anangle q2, (where q2=(c+d)/2) can be computed by the average of theangles c and d extracted by the second camera 24.

Accordingly, a coordinate (X3, Y3) of a new touch point Q can becomputed by the computed angles q1 and q2, and a distance between thefirst and second cameras 22 and 24. Therefore, the coordinate (X3, Y3)of the new touch point Q can be used as a reference coordinate when afunction corresponding to each touch mode is performed.

Referring again to FIG. 2, the operating system 50 provides a commandcorresponding to a control signal provided from the controller 40 to theuser interface (UI) 60. The user interface 60 performs a functioncorresponding to the command provided from the operating system 50.

When a first control signal is provided from the controller 40, theoperating system 50 can provide a first command corresponding to thefirst control signal to the user interface 60. Accordingly, the userinterface 60 can perform pressing of a mouse left button in response tothe first command.

A predetermined application is executed and displayed on the panel 70.When a user touches the panel 70 with one touch at a time, a one-touchis recognized by the first and second cameras 22 and 24, and thecoordinate of a touch point touched by the user is computed by thedigital processor 30.

The touch mode ‘1’ is selected by the controller 40 on the basis of thefrequency of touches recognized by the first and second cameras 22 and24, respectively, and accordingly, a first control signal is provided tothe operating system 50. At this point, the controller 40 can receivethe coordinate of the touch point touched by the user from the digitalprocessor 30 to provide the received coordinate to the operating system50. The operating system 50 provides a first command corresponding tothe first control signal together with the coordinate of the touch pointto the user interface 60. Therefore, the user interface 60 performspressing of a mouse left button at the touch point on the panel 70 inresponse to the first command.

When a second control signal is provided from the controller 40, theoperating system 50 can provide a second command corresponding to asecond control signal to the user interface 60. Accordingly, the userinterface 60 can perform pressing of a mouse right button in response tothe second command.

In the case where the user touches the panel 70 with two-touch at atime, one to two times of the frequency of touches are recognized by thefirst and second cameras 22 and 24, respectively, and the coordinates offirst and second touch points touched by the user are computed by thedigital processor 30.

The touch mode ‘2’ is selected by the controller 40 on the basis of thefrequency of touches recognized by the first and second cameras 22 and24, respectively, and accordingly, a second control signal is providedto the operating system 50. Also, the controller 40 can average anglesrecognized by the first and second cameras 22 and 24 in association withthe first and second touch points to compute a new touch point and acoordinate thereof and provide them to the operating system 50.

The operating system 50 provides a second command corresponding to thesecond control signal together with a new touch point to the userinterface 60. Therefore, the user interface 60 performs pressing of amouse right button at a new touch point on the panel 70 in response tothe second command. As soon as the pressing of the mouse right button isperformed, the user interface 60 can display a plurality of set menus.

In the case where a user touches the panel with five-touch at a time,one to five times of the frequency of touches are recognized by thefirst and second cameras 22 and 24, respectively, and the coordinates offive touch points touched by the user are computed by the digitalprocessor 30.

The touch mode ‘3’ is selected by the controller 40 on the basis of thefrequency of touches recognized by the first and second cameras 22 and24, respectively, and accordingly, a third control signal is provided tothe operating system 50. Also, the controller 40 can average anglesrecognized by the first and second cameras 22 and 24 in association withthe touch points to compute a new touch point and a coordinate thereofand provide them to the operating system 50.

The operating system 50 provides a third command corresponding to thethird control signal together with the new touch point to the userinterface 60. Therefore, the user interface 60 performs a mouse scrollbutton at a new touch point on the panel 70 to activate a mouse scrollin response to the third command.

In this case, a user should maintain five-touch of touch states. At thisstate, the user can scroll fingers to any one of up, down, left, andright directions. This scroll operation of the user is recognized by thefirst and second cameras 22 and 24, and corresponding information isdelivered to the user interface 60 by way of the digital processor 30,the controller 40, and the operating system 50. Accordingly, the userinterface 60 can move a screen displayed on the panel 70 along thescroll movement direction according to the user's scroll operation.

In the case where the user touches the panel 70 with ten-touch at atime, one to ten times of the frequency of touches are recognized by thefirst and second cameras 22 and 24, respectively, and the coordinates often touch points touched by the user are computed by the digitalprocessor 30.

The touch mode ‘4’ is selected by the controller 40 on the basis of thefrequency of touches recognized by the first and second cameras 22 and24, respectively, and accordingly, a fourth control signal is providedto the operating system 50. Also, the controller 40 can average anglesrecognized by the first and second cameras 22 and 24 in association withthe touch points to compute a new touch point and a coordinate thereofand provide them to the operating system 50.

The operating system 50 provides a fourth command corresponding to thefourth control signal together with the new touch point to the userinterface 60. Therefore, the user interface 60 turns on a virtualkeyboard and displays the virtual keyboard using the new touch point onthe panel 70 for a reference in response to the fourth command.

The display virtual keyboard can include character buttons, numericalbuttons, and command buttons. The user can manipulate the characterbuttons, the numerical buttons, and the command buttons of the displayedvirtual keyboard to input a desired character or number to the virtualkeyboard, and can give a desired command.

Meanwhile, in the case where the user touches the panel 70 ten-touch ata time again, the user interface 60 turns off the virtual keyboard toremove the virtual keyboard that is being displayed on the panel 70.

FIG. 9 is a flowchart explaining a method for driving a multi-touchsystem according to an embodiment.

Referring to FIGS. 1 to 9, whether the user touches the panel 70 isrecognized by the digital processor 30 (S110). When the user touches thepanel 70, the user's touch is generated as first and second imageinformation by the first and second cameras 22 and 24 disposed at thecorner regions 22 and 24 of the panel 70. The first and second imageinformation is provided to the digital processor 30. The digitalprocessor 30 can recognize the user's touch from the first and secondimage information provided from the first and second cameras 22 and 24.

The user's touch information and angle information can be displayed inthe first and second image information as illustrated in FIGS. 4A and4B. The touch information can represent the frequency of touches touchedat a time by a user, and the angle information can represent angles atwhich the touch points are recognized by the first and second cameras 22and 24.

The digital processor 30 extracts the frequency of touches and anglesfrom each of the first and second image information.

When the user's touch is recognized, the digital processor 30 computesthe coordinates of the touch points A and B on the basis of theextracted angle information and the distance information between thefirst and second cameras 22 and 24 set in advance (S113).

The frequency of touches, angles, and the coordinates of the touchpoints extracted from each of the first and second cameras 22 and 24 canbe stored in the first memory 80 (S116).

The digital processor 30 provides the frequency of touches, angles, andthe coordinates of the touch points extracted from each of the first andsecond cameras 22 and 24 to the controller 40.

The controller 40 sums the frequency of touches extracted from the firstcamera 22 and the frequency of touches extracted from the second camera24, selects a touch mode corresponding to the sum value from the secondmemory 85, and generates a control signal corresponding to the selectedtouch mode (S119).

Referring to FIG. 7, the sum values of the frequency of touchesextracted from the first camera 22 and the frequency of touchesextracted from the second camera 24, and the corresponding touch modesare set as a table in the second memory 85.

When the touch mode ‘1’ is selected, a first control signalcorresponding to the touch mode ‘1’ can be generated. When the touchmode ‘2’ is selected, a second control signal corresponding to the touchmode ‘2’ can be generated.

When the touch mode ‘3’ is selected, a third control signalcorresponding to the touch mode ‘3’ can be generated. When the touchmode ‘4’ is selected, a fourth control signal corresponding to the touchmode ‘4’ can be generated.

Meanwhile, when one of the touch modes ‘2’ to ‘4’ is selected, thecontroller 4 averages the angles of the touch points to compute anaverage angle, and computes the coordinate of a new touch point usingthe average angle (S122). The new touch point can be used as a referencepoint when a function which will be described later is performed.

The coordinate of the new touch point can be stored in the second memory85 (S125).

The generated control signal can be provided to the operating system 50together with the coordinate of the new touch point.

In the case where the touch mode ‘1’ is selected, since this correspondsto the case where the user has performed one touch, a new touch pointcannot be generated, and instead a touch point corresponding to onetouch, stored in the first memory 80, and provided by the digitalprocessor 30 can be provided to the operating system 50 together withthe above-generated control signal.

The operating system 50 generates a command corresponding to the controlsignal, and provides the command to the user interface 60 together witha touch point corresponding to one touch provided by the digitalprocessor 30, or a new touch point stored in the second memory 85(S128).

The user interface 60 performs a specific function in response to thecommand (S131).

When the command is a first command corresponding to the first controlsignal provided by the controller 40, pressing of a mouse left buttoncan be performed at a touch point corresponding to the one touch on thepanel 70 in response to the first command.

When the command is a second command corresponding to the second controlsignal provided by the controller 40, pressing of a mouse right buttoncan be performed at a new touch point on the panel 70 in response to thesecond command, and subsequently, a plurality of menus set in advancecan be displayed.

When the command is a third command corresponding to the third controlsignal provided by the controller 40, a mouse scroll button can beperformed in response to the third command. In this case, when a usertouches the panel 70 and scrolls in one of up, down, left, and rightdirections, an image displayed on the panel 70 can be moved along theuser's scroll direction from the new touch point on the panel 70.

When the command is a fourth command corresponding to the fourth controlsignal provided by the controller 40, a virtual keyboard can be turnedon in response to the fourth command and displayed on the new touchpoint on the panel 70. In this case, when the user touches the panel 70again, the virtual keyboard that is being displayed on the panel 70 canbe removed.

When the user's touch does not exist any more, a touch function can beended (S134).

Although the illustrated embodiment includes two cameras, the inventionis not limited thereto but can be implemented using three or morecameras are provided.

Although the invention has been described as employing cameras tocapture touch information, the invention is not limited thereto. Forexample the invention can be realized using in an IR matrix type imageconverter.

The present invention can set a plurality of touch modes and thus canrealize the functions of a plurality of input/output units using the setplurality of touch modes. The technical effect of the present inventionis to perform a plurality of functions using multi-touches on the paneland can be used in place of setting some icons on the panel tocorrespond to each function.

According to embodiments of the present invention, a plurality ofcameras are provided, and various input/output functions can be realizedaccording to the frequency of touches touched at a time, so that userconvenience can be maximized.

It will be apparent to those skilled in the art that variousmodifications and variation can be made in the present invention withoutdeparting from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A method for driving a multi-touch system, themethod comprising: capturing image information including fingers touchpoints of a user touched on a panel by each of at least two camera for aset of frames; extracting using a digital processor both touch frequencyand angle information of the user's touch points from the imageinformation; summing the touch frequency from each camera withoutcalculating positional information using a controller, wherein the touchfrequency has a threshold of at least 2; selecting a touch mode on thebasis of only the summed value of the touch frequencies using thecontroller; generating a control signal corresponding to the selectedtouch mode using the controller; and performing a touch function inresponse to the control signal using a user interface, wherein the imageinformation comprises a touch frequency of at least one touch and atleast one angle information.
 2. The method according to claim 1, whereinthe touch frequency is a count of concurrent touches in the imageinformation captured by one of the cameras.
 3. The method according toclaim 1, wherein each camera generates the image information for eachimage frame in a set of frames for a display having a predeterminednumber.
 4. The method according to claim 1, wherein the touch mode isselected when a sum value of the touch frequency of the at least onetouch in the generated image information for the cameras is includedwithin a range of sum values of the frequency of touches that correspondto the touch mode, for between 50 and 100% of the frames in the set offrames.
 5. The method according to claim 1, wherein the touch functionsimulates pressing of a mouse left button.
 6. The method according toclaim 1, wherein the touch function simulates pressing of a mouse rightbutton.
 7. The method according to claim 1, wherein the touch functionsimulates pressing of a mouse scroll button.
 8. The method according toclaim 1, wherein the touch function performs toggling the state of avirtual keyboard between an off state and an on state.
 9. The methodaccording to claim 5, further comprising computing a coordinate of atouch point using the angles extracted from the image information ofeach of the cameras, the simulated pressing of the mouse left buttonbeing performed at the touch point.
 10. The method according to claim 6,further comprising: averaging the angles of a user's touch pointsextracted from the image information of each of the cameras to computean average angle for each camera; and computing a coordinate of a newtouch point using the average angles, wherein simulating the pressing ofthe mouse right button is performed at the new touch point.
 11. Themethod according to claim 7, further comprising: averaging the angles ofthe user's touch points extracted from the image information of each ofthe cameras to compute average angles; and computing a coordinate of anew touch point using the average angles, wherein an image displayed ona panel is moved from the new touch point along the user's scroll in aspecific direction after simulating the pressing of the mouse scrollbutton.
 12. The method according to claim 8, further comprising:averaging the angles extracted from the each image information tocompute average angles; and computing a coordinate of a new touch pointusing the average angles, wherein the virtual keyboard is displayed atthe new touch point used as a reference.
 13. The method according toclaim 12, wherein the virtual keyboard that is being displayed isremoved by another touch of the user.
 14. A multi-touch systemcomprising: at least two cameras, each capturing image informationincluding fingers touch points of a user touched on a panel for a set offrames; a digital processor calculating both touch frequency and angleinformation of the user's touch points from each image informationwithout calculating positional information; a controller summing thetouch frequency from each image information, selecting a touch mode inresponse to only the summed value of the touch frequency and generatinga control signal corresponding to the selected touch mode, wherein thetouch frequency has a threshold of at least 2; an operating systemgenerating a command corresponding to the control signal to provide thecommand to the user interface; and a user interface performing a touchfunction in response to the command, wherein the image informationcomprises a touch frequency of at least one touch and at least one angleinformation.
 15. The system according to claim 14, wherein the touchrecognition unit includes at least two cameras.
 16. The system accordingto claim 15, wherein the at least two cameras are disposed at cornerregions of a panel.
 17. The system according to claim 14, wherein thetouch recognition unit includes a plurality of infrared sensors and aplurality of photo sensors.
 18. The system according to claim 14,wherein the controller averages the angles extracted from the each imageinformation to compute an average angle for reach image information, andcomputes a coordinate of a new touch point using the computed averageangles to provide the new touch point to the user interface, and theuser interface performs the touch function using the new touch point asa reference.